Thorax Flashcards
What is the thorax, and where is it located?
The thorax is the part of the body between the neck and abdomen, commonly referred to as the chest.
How does the thorax differ from the chest?
The term “chest” is broader and includes more structures than the thoracic wall and cavity, such as the pectoral girdle and breast tissue.
What are the major functions of the thoracic cavity?
The thoracic cavity houses organs of the respiratory and cardiovascular systems, provides protection for vital organs, and facilitates breathing.
How is the thoracic cavity divided?
It is divided into the mediastinum, which contains the heart and other structures, and two pulmonary cavities that house the lungs.
What organs occupy the pulmonary cavities in the thorax?
The lungs occupy the pulmonary cavities.
What is the mediastinum, and what does it contain?
The mediastinum is the central compartment of the thoracic cavity, containing the heart, esophagus, trachea, and major blood vessels.
What is the shape of the thoracic cavity, and how does it change from top to bottom?
The thoracic cavity is shaped like a truncated cone, narrowing superiorly and widening inferiorly.
What bones form the pectoral girdle?
The pectoral girdle is formed by the clavicles and scapulae.
What is the thoracic skeleton composed of?
It is composed of 12 pairs of ribs, the sternum, and 12 thoracic vertebrae with their intervertebral discs.
How does the thoracic wall protect abdominal organs?
The lower half of the thoracic wall surrounds and protects some abdominal viscera, such as the liver.
What is the relationship between the thoracic diaphragm and the thoracic cavity?
The diaphragm forms the floor of the thoracic cavity, separating it from the abdominal cavity.
What are the functions of the lungs?
The lungs provide for the exchange of oxygen and carbon dioxide between the air and the blood.
How do nutrients traverse the thoracic cavity?
Nutrients pass through the thoracic cavity via the esophagus, traveling from the head to the abdomen.
Why are the mammary glands discussed in the context of the thorax?
Although functionally related to the reproductive system, the mammary glands are located on the thoracic wall.
What constitutes the true thoracic wall?
The true thoracic wall includes the thoracic cage, muscles, skin, subcutaneous tissue, and fascia.
Where are the mammary glands located?
They lie within the subcutaneous tissue of the thoracic wall
What is the function of the thoracic cage?
It protects vital organs, supports the upper limbs, and provides attachment for various muscles.
How do ribs contribute to the structure of the thoracic wall?
Ribs form the main structure of the thoracic wall, providing rigidity and protection.
What is the significance of the thoracic cage’s joints?
The joints allow for movement and flexibility, which are essential for breathing.
How do changes in the shape of the thoracic cage support respiration?
Movements of the thoracic cage during breathing change the volume of the thoracic cavity, aiding air exchange.
What factors contribute to the rigidity of the thoracic cage?
Its shape and osteocartilaginous elements contribute to rigidity, while joints and flexible ribs allow for movement.
How do intercostal spaces support the function of the thorax?
They contain muscles, nerves, and vessels that assist in respiration and other functions.
What are the types of ribs found in the thoracic skeleton?
There are true ribs (1-7), false ribs (8-10), and floating ribs (11-12).
How are typical ribs different from atypical ribs?
Typical ribs (3-9) share common structural features, while atypical ribs (1, 2, 10-12) have unique characteristics.
What features are common to typical ribs?
Typical ribs have a head, neck, tubercle, and body with a costal groove for neurovascular protection.
How do false ribs differ from true ribs?
False ribs connect indirectly to the sternum via the costal cartilage of the rib above them.
What characterizes floating ribs?
Floating ribs do not connect to the sternum or other ribs anteriorly; their ends are embedded in muscle.
What is the function of costal cartilages in the thorax?
They provide flexibility to the thoracic wall, allowing movement and expansion during breathing.
How are intercostal spaces named and organized?
They are named for the rib forming their superior boundary, with 11 spaces in total.
What structures occupy the intercostal spaces?
Intercostal spaces contain muscles, membranes, blood vessels, and nerves.
What are the key features of thoracic vertebrae?
Thoracic vertebrae have costal facets for rib attachment and long, downward-sloping spinous processes.
How do costal facets on thoracic vertebrae facilitate rib attachment?
They allow ribs to articulate with the vertebrae at joints of the head of the rib and costotransverse joints.
What is the sternum, and what are its parts?
The sternum is a flat bone located in the anterior thorax, consisting of the manubrium, body, and xiphoid process.
What is the function of the xiphoid process in the sternum?
It serves as a landmark for the inferior border of the heart and attachment for the diaphragm and abdominal muscles.
What are the superior and inferior thoracic apertures?
They are openings at the top and bottom of the thoracic cage that allow passage of structures between the thorax, neck, and abdomen.
What structures pass through the superior thoracic aperture?
The trachea, esophagus, nerves, and blood vessels that supply the head, neck, and upper limbs.
How does the diaphragm separate the thoracic and abdominal cavities?
It completely occludes the inferior thoracic aperture and controls the volume of the thoracic cavity.
What is the role of the diaphragm in breathing?
The diaphragm contracts to increase the vertical dimension of the thoracic cavity during inspiration.
How does the thoracic cavity change during inspiration?
The volume increases as the thoracic wall expands and the diaphragm contracts.
What happens to the thoracic cavity during expiration?
The volume decreases due to the elastic recoil of the lungs and relaxation of respiratory muscles.
How do the pump-handle and bucket-handle movements aid respiration?
Pump-handle movement increases the anteroposterior dimension, while bucket-handle movement increases the transverse dimension.
What is the clinical significance of the superior thoracic aperture?
It can be a site of compression or obstruction affecting structures such as the brachial plexus and subclavian vessels.
How do ribs move during breathing?
They elevate during inspiration and depress during expiration, increasing and decreasing thoracic volume.
What are costovertebral joints?
They are joints where the heads of the ribs articulate with the bodies of thoracic vertebrae.
What ligaments support costovertebral joints?
Ligaments such as the radiate ligament and the intra-articular ligament.
How are costotransverse joints structured?
They form between the tubercle of the rib and the transverse process of the vertebra.
What is the function of the sternocostal joints?
They connect the ribs to the sternum, allowing for movement during breathing.
What distinguishes the manubriosternal joint from other sternal joints?
It is a cartilaginous joint that may fuse with age, forming the sternal angle.
What types of movement occur at costotransverse joints?
Rotation and gliding movements, allowing rib elevation and depression.
How do the true muscles of the thoracic wall differ from accessory muscles?
True thoracic muscles are directly involved in moving the thoracic cage, while accessory muscles assist during deep or forceful respiration.
What is the role of the pectoralis muscles in respiration?
They can act as accessory muscles, helping to elevate the ribs during deep breathing.
How do the scalene muscles contribute to thoracic movement?
They stabilize the first two ribs, enabling other muscles to elevate the lower ribs during inspiration.
What are the main muscles that occupy the intercostal spaces?
The external, internal, and innermost intercostal muscles.
How do the external intercostal muscles contribute to respiration?
They elevate the ribs during inspiration, increasing the thoracic cavity’s volume.
What is the function of the internal intercostal muscles?
They depress the ribs during forced expiration, decreasing thoracic cavity volume.
How do the serratus posterior muscles influence thoracic movements?
They are thought to have a proprioceptive function rather than a primary role in respiration.
What is the proprioceptive function of the thoracic wall muscles?
These muscles may help sense the position and movement of the thoracic cage.
What are the functions of the levatores costarum muscles?
They assist in rib elevation, although their role in normal respiration is not well established.
What structures are attached to the xiphoid process?
The diaphragm, rectus abdominis muscle, and transversus thoracis muscles attach to the xiphoid process
Why are rib fractures more common in the middle ribs than in the upper or lower ribs?
The middle ribs are more exposed and less protected by the pectoral and scapular muscles.
What is the clinical consequence of rib fractures?
Rib fractures can cause significant pain, restrict breathing, and potentially damage internal organs.
What is a flail chest, and how does it affect breathing?
Flail chest occurs when multiple rib fractures allow a portion of the thoracic wall to move independently, leading to paradoxical movements that impair ventilation.
What is thoracotomy, and why is it performed?
Thoracotomy is a surgical procedure to access the thoracic cavity, often for lung or heart surgery
What is a median sternotomy, and when is it used?
It involves splitting the sternum along the midline to access the thoracic cavity, typically used in cardiac surgery.
Why might the sternum be used for bone marrow biopsies?
The sternum’s subcutaneous position and vascular spongy bone make it accessible for sampling.
What developmental anomalies can affect the sternum?
Conditions like pectus excavatum (sunken chest) or pectus carinatum (protruding chest) can occur if the sternum’s halves do not fuse properly.
How can the superior thoracic aperture lead to thoracic outlet syndrome?
Compression of nerves or blood vessels passing through the superior thoracic aperture can cause symptoms in the upper limbs.
What is rib dislocation, and what are its common symptoms?
Rib dislocation occurs when the costal cartilage separates from the sternum, leading to localized pain and deformity.
What can cause separation of the costochondral joints?
Trauma or severe stress to the rib cage can cause these joints to separate, resulting in pain and instability.
What are the consequences of diaphragm paralysis?
Paralysis causes paradoxical movement, impairing the efficiency of breathing.
How do the thoracic nerves contribute to the innervation of the thoracic wall?
Thoracic nerves provide motor and sensory innervation to the intercostal muscles, skin, and parietal pleura.
What is the significance of the costal groove on a rib?
It protects the intercostal nerves and vessels running along the rib.
What are intercostal spaces, and what do they contain?
Intercostal spaces are gaps between adjacent ribs, containing muscles, nerves, and vessels.
How do the movements of the thoracic wall affect lung pressures?
Expansion decreases intrapulmonary pressure, drawing air in, while compression increases pressure, expelling air.
What is the “bucket-handle” movement, and how does it contribute to breathing?
This lateral rib elevation increases the thoracic cavity’s transverse diameter.
What is the “pump-handle” movement, and how does it contribute to breathing?
This anterior rib elevation increases the thoracic cavity’s anteroposterior diameter.
What is the function of the intercostal muscles during normal and forced breathing?
They stabilize the thoracic wall during quiet breathing and elevate or depress ribs during forced respiration.
What is the anatomical arrangement of the intercostal nerves and vessels?
They run along the costal groove on the inferior border of the rib
What structures pass through the openings in the diaphragm?
The aorta, esophagus, and inferior vena cava pass through the diaphragm.
What is thoracic outlet syndrome, and what are the common symptoms?
It is a condition where nerves or blood vessels are compressed, leading to pain, numbness, or weakness in the upper limbs
What ligaments support the costotransverse joints?
The superior, lateral, and posterior costotransverse ligaments
What is the anatomical significance of the sternal angle?
It marks the junction of the manubrium and body of the sternum, used as a landmark for rib counting.
What muscles are involved in deep inspiration?
The diaphragm, external intercostal muscles, scalene muscles, and sternocleidomastoid.
What happens to the diaphragm during expiration?
It relaxes and ascends, decreasing the thoracic cavity’s vertical dimension.
How do the intercostal spaces change during respiration?
They widen during inspiration and narrow during expiration.
How does aging affect the thoracic wall?
The costal cartilages may ossify, reducing flexibility, and the thoracic cage may become more rigid.
What distinguishes true ribs from other types of ribs?
True ribs connect directly to the sternum via costal cartilage
What structural differences are seen in the atypical ribs?
Atypical ribs (1, 2, 10-12) have unique features like different articulations or shorter lengths.
Why might a rib fracture lead to a pneumothorax?
A fractured rib can puncture the pleura, causing air to enter the pleural space.
What is the manubrium, and what are its anatomical features?
The manubrium is the upper part of the sternum, with notches for clavicle and rib articulation.
How does the diaphragm separate the thoracic and abdominal cavities?
It forms a muscular partition that closes the inferior thoracic aperture.
What factors determine the movement at costotransverse joints?
The shape of the rib tubercle and the transverse process determine the degree of rotation or gliding.
What role do the subcostal muscles play in breathing?
They help depress the ribs during forced expiration.
How do changes in the diaphragm’s shape affect thoracic volume?
Flattening increases thoracic volume, while doming reduces it.
Why is the diaphragm considered the primary muscle of respiration?
It is the main muscle that changes thoracic volume during breathing.
What is paradoxical breathing, and when might it occur?
It occurs when the paralyzed side of the diaphragm moves oppositely during breathing.
What is the function of the superior thoracic aperture?
It allows passage of structures between the thorax and neck.
Why is the inferior thoracic aperture wider than the superior?
It accommodates the larger abdominal organs below the diaphragm.
How do the scalene muscles stabilize the first rib?
They fix the first rib, allowing the intercostal muscles to elevate the lower ribs more effectively.
What is the clinical significance of the xiphoid process in CPR?
Incorrect hand placement over the xiphoid can cause injury during chest compressions
How does the xiphoid process change with age?
It often ossifies and fuses with the body of the sternum in people over 40 years old.
What role does the xiphoid process play in the attachment of muscles?
It provides attachment points for the diaphragm, rectus abdominis, and transversus thoracis muscles.
What occurs during rib separation, and what are its symptoms?
The rib and its costal cartilage separate at the costochondral junction, causing pain and instability.
How are the levatores costarum muscles involved in rib movement?
They help elevate the ribs, although they mainly play a proprioceptive role.
What happens to the thoracic cavity’s dimensions during deep inspiration?
It expands in all directions: vertically, anteroposteriorly, and transversely.
Why is the thoracic wall’s flexibility important for respiration?
It allows the expansion and contraction of the thoracic cavity, facilitating air movement in and out of the lungs.
What is the function of the intercostal nerve branches?
They provide motor innervation to intercostal muscles and sensory innervation to the skin and parietal pleura.
How do the pectoralis major and minor assist during forced respiration?
They elevate the ribs when the upper limbs are fixed, helping to expand the thoracic cavity.
What anatomical structures form the boundaries of the superior thoracic aperture?
The manubrium, the first rib, and the first thoracic vertebra
What types of movements are allowed at the costovertebral joints?
Rotation and gliding, which contribute to rib movement during respiration.
Why might the thoracic wall’s structure contribute to susceptibility to rib fractures?
The ribs’ thin structure and the lack of protection by thick muscles can make them prone to fractures.
How do the intercostal muscles contribute to changing the pressure within the thoracic cavity?
They alter the volume of the cavity by elevating or depressing the ribs, which changes intrathoracic pressure.
What are the three layers of intercostal muscles, and what is their orientation?
The external, internal, and innermost intercostal muscles, with fibers running in different directions for each layer.
Why is it important to avoid compressing the xiphoid process during CPR?
Compression can cause the xiphoid process to break and damage internal organs
What forms the floor of the thoracic cavity, and what is its role in respiration?
The diaphragm forms the floor, and it contracts to increase thoracic volume during inspiration.
What is the clinical significance of the manubriosternal joint in relation to rib counting?
The sternal angle at this joint is used as a landmark to locate the second rib.
How do accessory muscles aid respiration during physical exertion?
They assist in elevating the ribs and expanding the thoracic cavity during forced inspiration.
What changes occur in the diaphragm during forced expiration?
The diaphragm relaxes and ascends further, decreasing thoracic volume.
How does the diaphragm contribute to venous blood return?
The downward movement of the diaphragm during inspiration decreases thoracic pressure, aiding venous return.
Why is the inferior thoracic aperture larger than the superior thoracic aperture?
It allows for a greater passage of structures between the thorax and the abdominal cavity.
What is the role of the transversus thoracis in the thoracic wall?
It helps depress the ribs during forced expiration.
How do changes in the structure of the thoracic wall affect respiration in older adults?
Calcification of costal cartilages reduces the flexibility of the thoracic wall, impairing breathing efficiency.
What are the typical consequences of a first rib fracture?
It can damage the subclavian vessels and the brachial plexus due to its proximity.
What anatomical structures are connected by the costotransverse joints?
Conditions like supernumerary ribs (extra ribs) or variations in the sternum’s shape.
How do intercostal arteries contribute to the thoracic wall’s blood supply?
They run along the intercostal spaces and provide blood to the intercostal muscles and adjacent structures.
What are some anatomical variations that can affect the thoracic wall?
Conditions like supernumerary ribs (extra ribs) or variations in the sternum’s shape.
What is the function of the diaphragm’s central tendon?
It provides a point of convergence for the diaphragm’s muscle fibers, aiding in its movement during breathing.
What are the effects of a thoracic cage injury on respiration?
Injuries can limit chest expansion and impair lung function.
What distinguishes the first rib’s anatomy from other ribs?
It is shorter, wider, and more curved, with only one articular facet.
How does the thoracic wall assist in actions like coughing?
The muscles compress the thoracic cavity, generating force to expel air.
What is the significance of costal cartilage flexibility in the thoracic wall?
It allows the rib cage to expand and contract during respiration.
What is the primary function of the internal thoracic artery?
It supplies blood to the anterior thoracic wall and upper abdominal structures.
How does the diaphragm’s movement affect intra-abdominal organs during respiration?
Its descent during inspiration compresses abdominal organs, while its ascent during expiration relieves the pressure.
What are the potential risks associated with rib fractures?
Risks include damage to the lungs, pleura, and other internal organs.
What muscles are considered accessory respiratory muscles?
The pectoralis major and minor, scalene muscles, and sternocleidomastoid.
What happens to the diaphragm during quiet breathing?
It contracts slightly, expanding the thoracic cavity to draw air into the lungs.
What is the significance of intercostal nerve blocks in pain management?
They can provide relief for pain associated with rib fractures, surgical incisions, or shingles.
How does the superior thoracic aperture facilitate respiration?
It allows air to flow into and out of the respiratory tract.
What changes occur in the rib cage during physical activity?
The rib cage expands more widely, increasing lung capacity for greater oxygen intake.
How do intercostal veins drain blood from the thoracic wall?
They drain into the azygos vein system, which ultimately returns blood to the superior vena cava.
What structures are at risk during a thoracotomy?
The intercostal nerves, blood vessels, and underlying lung tissue.
How do the true ribs contribute to the structural integrity of the thoracic cage?
Their direct attachment to the sternum provides stability to the anterior thoracic wall.
What role do the intercostal muscles play during coughing or sneezing?
They contract forcefully to increase thoracic pressure and expel air from the lungs.
Why are rib separations and dislocations common in athletes?
High-impact activities and contact sports increase the risk of thoracic injuries.
How does the diaphragm’s function change when a person is lying down?
The diaphragm must work harder against gravity to expand the thoracic cavity.
What factors can affect the movements of the thoracic wall?
Age, muscle strength, rib flexibility, and respiratory conditions.
How does rib movement aid in increasing the thoracic cavity volume?
Ribs move outward and upward during inspiration, expanding the thoracic space.
What is the significance of the diaphragm’s attachment to the lumbar vertebrae?
It provides a strong anchor point for the diaphragm’s muscle fibers.
How do intercostal muscles contribute to stabilizing the thoracic wall?
They maintain tension and control movements between adjacent ribs.
What is the function of the serratus anterior muscle in breathing?
It can elevate the ribs when the scapula is fixed, assisting in forced inspiration.
How does the diaphragm’s central tendon support its respiratory function?
It enables the diaphragm to maintain its shape while contracting and expanding.
What changes occur in the diaphragm during physical exertion?
It contracts more forcefully, increasing the volume of the thoracic cavity for greater oxygen intake.
